纳米磁性微粒固定化纤维素酶及水解秸秆的研究

The Study Immobilization of Cellulase on Nanometer Magnetic PEG Microsphere and Hydrolization of Stalk

采用共沉淀法制备出纳米聚乙二醇磁性微粒,扫描电镜观察表明微粒呈近似球形、表面粗糙,粒径均匀(100～200 nm),无磁场下稳定分散于水中,有磁场时迅速沉降.以戊二醛为交联剂,采用吸附交联法将纤维素酶固载到纳米磁性微粒上,制备出磁性固定化纤维素酶,考查了不同固定化条件对固定化酶的影响,确定最佳固定化条件为:0.2 g微粒,20 mg纤维素酶,0.15%戊二醛.动力学研究表明磁性固定化纤维素酶的最适温度为50℃,最适pH值为4.5,表观米氏常数Km和最大反应速度Vmax分别为Km=4.48 mg/mL,Vmax=2.38 mg/(mL h 1).稳定性试验表明磁性固定化纤维素酶较游离酶热稳定性有所提高,pH值稳定性增加,磁性固定化酶连续使用10批次后,其活性仍可保持59%.磁性固定化纤维素酶对盐酸、液氨/硫氰酸氨预处理后的玉米秸秆及滤纸水解得糖率分别为23.6%、20.9%和32.0%.

This paper establishes a foundation for producting the fuel alcohol through diluting the straws. Nanometer Magnetic PEG Microsphere were prepared by technology of coprecipitation. The microsphere have 100-200 nm diameter, rough surface and approximate globular through viewing of SEM. They have good magnetic respon- sibility in presence of magnetic field and dispersion stability in water. Cellulase was immobilized on nanometer Magnetic PEG Microsphere by adsorbing and cross link. The result indicated that the optimum condition of immobilization were 0.2 g microparticle, 20 mg cellulose, 0.15% glutaral. Kinesic esearch indicated that the optimal temperature is 50℃, optimal pH is 4.5, Km=4.48 mg/mL, Vmax=2.38 mg/（mLh-1）. Stability test indicated that immobilized cellulose is better than free cellulose in heat stability and pH stability. The immobilized cellulose can keep activity about 59% after consecutively used 10 batches. The Sugar yield of enzymolysis pretreated on Stalk and filter-paper using is 23.6%, 20.9%, 32.0%.